With the future of the planet in grave danger, some far-sighted builders decide that it’s best for humanity to build a subterranean city into which they can retreat. It’s got to be something self-sustaining as they are going to be down there for a couple of centuries. They do provide exit instructions, but over time they get lost and so nobody knows that maybe it’s time to resurface. Now, though, the engineering is starting to give up the ghost and that means power and food are becoming rationed. The mayor (Bill Murray) is hopelessly out of his depth/obsessed with his own position and the…